code: def test_convert_aliases(tmp_path, orig_dtype, alias, expected_dtype):
      orig_fname = tmp_path / "orig.nii"
      out_fname = tmp_path / "out.nii"
  
      arr = np.arange(24).reshape((2, 3, 4))
      img = nib.Nifti1Image(arr, np.eye(4), dtype=orig_dtype)
      img.to_filename(orig_fname)
  
      assert orig_fname.exists()
      assert not out_fname.exists()
  
      convert.main(
          [str(orig_fname), str(out_fname), "--out-dtype", alias]
      )
      assert out_fname.is_file()
  
      expected_dtype = np.dtype(expected_dtype).newbyteorder(
          img.header.endianness
      )
  
      converted = nib.load(out_fname)
      assert converted.get_data_dtype() == expected_dtype
  
file_path: nibabel/nibabel/cmdline/tests/test_convert.py
imports: import numpy
  import pytest
  import nibabel
  from nibabel.cmdline import convert
  from nibabel.testing import get_test_data
label_desc: Use image node_id 6 for calling a global function with example usage: test_convert_aliases(tmp_path, orig_dtype, alias, expected_dtype) without return types